Beef conference draws big crowd
for Tri-State Livestock News
Reproduction is the foundation upon which all other factors concerning living things are built. The cattle industry is no different, as evidenced by the number of people in attendance at the Applied Reproductive Strategies in Beef Cattle conference held Dec. 3-4, at the Ramkota Hotel and Convention Center in Sioux Falls, SD. Three hundred and fifty commercial cattlemen, seedstock producers, veterinarians, and others were present at the convention, along with an additional 30-40 listening to each presentation live via the Web.
The event has been held yearly between rotating states as far east as Kentucky and as far west as Idaho. This year was South Dakota’s opportunity, and with these numbers it proved to be the second largest so far.
Topics covered during the event included heifer maintenance, control of estrus, timing of A.I., managing bull development, DNA testing, handling of frozen semen, nutrition, cattle temperament, vaccination, embryo transfer, and sexed semen.
One of the first speakers was Dr. Eric Mousel of the Dept. of Agricultural Sciences at Northwest Missouri State University. His presentation was “Effect of Heifer Calving Date on Longevity and Lifetime Productivity.”
Dr. Mousel began by saying fertility is a key component of longevity in the cow herd. Early calving increases both longevity and productivity. Females with longer reproductive lives wean more calves and thus have the potential for a higher lifetime weaning weight average.
He cited a survey which indicated that 33 percent of cows are culled because they don’t become pregnant; it also reported that 15.6 percent of all culled cows leave the herd before age five, and still another 31.8 percent leave between five and nine years of age. It takes five calves to pay for the development costs and annual maintenance of a replacement heifer. It makes sense to manage the herd to reduce the number of cows culled at a young age.
One such management practice is to ensure that heifers conceive in their first breeding season. If they breed early, that is even more desirable as they will calve early. This helps ensure that they will have time to recover for rebreeding. “Get early calvers in the herd and keep them in the herd,” emphasized Dr. Mousel. “Increased profitability will result.”
“Insemination Related Factors Affecting Fertilization in Cattle” was covered by Dr. Joseph Dalton, Associate Professor of the Dept. of Animal and Veterinary Science at the University of Idaho.
Dr. Dalton listed a number of elements that are important to fertilization. Semen quality and number of sperm topped the list, followed closely by accessory sperm, bull effect plus timing of A.I., semen handling, and fertility associated antigen.
Accessory sperm identification is a research technique which involves quantifying the number of sperm trapped in an embryo which has been recovered by uterine flushing six days after A.I. Accessory sperm are thought to be a measure of sperm available and competing for fertilization.
Bull effect refers to a bull’s ability (or inability) to gain access to the egg. For example, a large number of sperm from a particular bull that reach the egg may indicate that this bull may be less vulnerable to semen handling and insemination errors.
As for handling of semen, how many straws should be thawed at one time? Dr. Dalton says, “Know your comfort zone.” Handle no more than can be used in 10-15 minutes. Do not allow straws to touch one another when thawing, and use multiple thaw baths if possible. “Time, temperature, hygiene, and skill are the important factors here,” added Dr. Dalton.
Fertility associated antigen (FAA) is a protein on the sperm cells of some bulls which is absent on those of others. It was initially felt that FAA-positive bulls are more fertile; however, further testing did not support this theory.
Following a dinner of beef brisket on Monday evening, attendees were able to rotate through several hands-on work stations. These included ultrasound of a pregnant uterus, semen handling, an A.I. simulation box, an embryo development display, synchronization injections, a carcass quality display, and taste testing of different quality grades of beef. There was also an exhibit of six Angus heifers which had been DNA tested for marbling and rate of gain, with printouts of their individual scores available. A trade show was in operation both days of the conference.
The event was hosted by the Beef Reproduction Task Force, the Beef Reproduction Leadership Team, and South Dakota State University in cooperation with the University of Missouri Conference Office.